Starter jaw actuating mechanism



Oct. 23, 1951 R. w. sTELzl-:L 2,572,532

STARTER JAW ACTUATING MECHANISM Filed Nov. 7, 1949 R INVENToR.

PODER/CK W. TELZEL Patented Oct. 23, 1951 Roderick W. Stelzel, Hohokus, N. J., assgnor to Bendix Aviation Corporation, Tcterboro, N. J., a corporation of Delaware Application November 7, 1949, Serial No. 125,923

6 Claims.

The present invention relates to engine starters and particularly to starter jaw advancing mechanism.

In engine starters some means are necessary to advance the starter jaw into engagement with the engine jaw upon energization of the starter. One method used is a friction ring in contact with the starter jaw to hold the jaw momentarily against rotation to enable the screw shaft and spline nut to coact to move the jaw into engagement. Also the friction ring serves to hold the starter jaw in its retracted position when the engine is running. This method has numerous disadvantages, some of which are that friction means are present during the operation of the starter, the friction ring becomes worn and does not have suicient friction to hold the jaw against rotation and to hold the jaw in its retracted position when the engine is running. This is especially a disadvantage when the starter is mounted with the jaws downward as is required in many installations. Also the friction means do not per-l form satisfactorily when low temperatures are encountered.

Itis an object of my invention to provide a positive jaw advancing mechanism incorporating positive holding means that will overcome the above difficulties.

Another object of the invention is to provide an improved starter.

Another object is to provide an improved starter for operation at low temperatures.

Another object is to provide an improved jaw advancing mechanism for use in engine starters.

Another object is to provide means for preventing the jaws from becoming engaged by vibration when the engine is running.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein one embodiment of the invention is illustrated by way of example.

In the drawing:

The single figure is a sectional View of an engine starter embodying one form of the inven- 9 carried by spider cage IIJ, The planet gears '7y mesh with a ring gear II shown as integral with gear housing I2. The gear housing I2 is secured to the motor housing 5 by studs I3 and nuts I4 as shown or by othersuitable means. y

Integral with the spider cage I0 is a pinion gear I5 adapted to engage planetgears I6 which alsoV engage the ring gear II. The gears I6 are supported by bearings I1 mounted on stub shafts I8 l carried by a drum member I9. The drum mem'- ber or barrel I9 is rotatably mounted in vthe housing I2 by bearing 20..

The barrel I9 is connected for the transmission of rotary motion to axially stationary spline nutA '-2I through a torque limiting disc pack 22. The'V disc pack 22 comprises a plurality of friction discs alternately splined to the inner face of the barrel I9 and the outer face of the spline nut 2|. The discs of the pack 22 are forced into frictional engagement with each other by a plurality of circumferentially spaced springs 23 compressed between a ange 24 on the spline nut 2I andan adjustable nut 25 threaded into the bar` rel I9 and set so that the disc pack 22 will slip at a predetermined torque.

The long lead internal threads of the splinenut 2I mesh with mating threads of screw shaft 26 which is connected to starter jaw 21 by axial splines 28 for rotation therewith.

The present invention provides novel means for actuating the starter jaw 21 into engagement with a crank shaft 29 or extension thereof of the engine to be started.

The pinion gear I5 has a shaft 30 extending axially therefrom into the barrel I9. The shaft 30 is secured to the gear I5 by a key 3|, or in any other suitable manner such as splines forv rotation therewith. The shaft 33 terminates in an enlarged portion or head 32 and is axially positioned by means of a retaining ring 33 adapted to fit in a groove 34 in the shaft 30 and thrust washers 35 positioned between the head 32 and the radial wall of the barrel I9. The screw shaft 26 has an internally helical threaded portion 36 terminating in a circumferential groove 31. The end of the screw shaft 26 adjacent to the groove 31 has a chamfer 38. The head 32 has a plurality of holes 39 spaced around its circumference and extending radially inward thereof. 'The holes 39 are so positioned in relation to each other so that the center lines thereof form an angle equal to the pitch angle of the helical threaded portion 36. A ball 4I] adapted to mesh with the threaded portion 36 is secured in each hole 3Q -by peening the edge Yof the hole 39 or in any other suitable manner. Springs 4l urge the balls 40 radially outward into engagement with the threaded portion 36. A plurality of balls 42 adapted to mesh with the circumferential groove 31 when the shaft 26 is in its retracted position are mounted in the head 32 in holes 43 spaced circumferentiaily argued the head??- .ball 4 2 are retain in thehojles e43 by peeningvfo'ni' other suitable manner; Springs44' urgeV the balls' 42 radially outward into operative position.

The clutch jaw 21 is retained in operative position relative to the screw shaft; by a meshv rod 45 secured to the clutch jaw r2,1 by anut 4Q. The mesh rod 45 extends axially i t lscrew shaft 26 and terminates in4 a' circumifentiai flange 41. A flange 48 of screw shaft 2B extending radially inwardly coacts with the flange 4 1 ito limit the outward movement of the mesh rod ,45. A spring 49 coacts with the ange 48 to bias the: iw 21 ,Oliiwgfi- Y An* oil se'al 50 surrounds the outer circumferbf tbe blaten jaw 21 au@l is herum position y br cl et l 4clarpfed between the 'ange' 52on the "gear housing l2- and engine' crank 'case 53 by means ot studs 54 and nuts 55 or in any other suitable manner.

operation,4 whenthe motor I is energized rotary motion isimparted to the barrel I9 by means ot the planetary gearsystem which includes theupinion l5. The shaft 30A being keyed to the pinion` l5 rotates therewith; The balls i0 oo act withnthe helicalthreadedV portion 3B prd- 'Ig al 'screw-like action which causes thebal'l's 4g to'be ra'heted but bf circumferential groove 31, the force of the s r'grings"H vbeing greater than that 0f bh Springs 44 andfdrives the s'crewjsha'f/t axially outward. This action is accelerated by the'ba itibuthebaus in Will haveiravledlit dftiihelical threaded por# non 3s une tbe circumferential groove v:im l The obavarrtraveijjf tnefbaus :it bemgiiniited Abv the peenmgwill have ebrea `from the Sides Yferential groove '31,' thus andidr'ag' of these parts xg cranked. Should the to ratchet in lik' 'inan`he'r'^ l inasmuch as lth speed of rotation of the shaft lilis gred Yer than met @rufe barella; the jaw 2r' f vea uit@ ement With a relatively small am utm'of Idee n, of the barra. The leeliigiiiiiii connection between the spline nut 2i and thy scretvshaft 25 permitsmthe screwnshaft, 2 51to be pushed along thespliiiesby ihescreW-likeaeiio ofuthe connection between the shaft 36 and the srewheii 2,6. ,n e. Uren ih e engiiietartiiia. theme29 overrides ihajaw ?1.. fgrciiis it inverti, wherein.. theY balls 49 Willprerrideths .ihredsi Upea the jaw?? misi .Safer ,etait @enligne .i9 the ietraild. rositiqri, the balls izsngagedths groeve. aiiiire.- venthmoyementufrqmthe retracted position when the en ine is unning e the ball-sA starter is mounted with the jaw downward as is necessary for some installations.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangements of the parts may be made to suit requirements.

Whvelis @aimed is: Y

1. For usein 'engine' "starter, the combination of an assembly comprising an axially stationary rotatable spline nut, a screw shaft connected for rotation with and axial movement relative to said splinewnut-Asaid screw shaft having an inreaded portion, and an annular groove hereto; afshaft member concentric with said screw shaft, said shaft member having i'st ball receiving openings at spaced intervals along a helical path correspondin g tQ the pitch of said internally threaded portii, balls positioned in said openings, rst spring means for resilientlybiasingsaid balls into pgn with saidinternallythreaded portn, see' nu b'u receiving openings in sardshft spaced rcircumferentially around said shaft: se'corrd ballsV rfo's'iti'tzr'iedv inA said* secondv Oberlin second spring means' for biasing` said sebcnd s; engagement withsaid annular groove to d saids'ciew shaft ina retracted position; said t spring means, being greater than said last spri I g means `whereby u pon rotation of said shaft' said scr'ewjs'laftis actuat'ed toganje'xten'ded position.

2; Ihem'cmbination as' defined in claim 1 arid includingva conical ramp' portion ofY said screw shaft, s'ai'dramp p'ortionbeing positioned to coact With j'd`Cd blsd balls Wh'l Sad screw shaft vis viii a partlally extended positiritv ard axial movement of said screw shaft to the extended position.

3. In ari engine' tarte?, the bmb'iaubr ''f ii assembly/' 'eoinbr'slrrg 'an axially Astationrrv lia/'table swpln nut, a shaft in Sad hilt arid splinedtherto i'rz vaxial movement relative t' and rotatin therewith, a `starter jaw member adapted fbi rotation with and amai fvmnt by vsaid screw shaft, means including a positive drivenY member for actuating said screw shaft t0 lf? leed@ Staffe? ially i0 menging er: gaging position, yieldabie means Ator drivably Coiirliing, Seidfnenperie said screw Shad. Said' last means being adapted torelease said connectionwhen the oppositionto Yaxial movement of said starter jaw exeedsa predetermined maxishattlin a retracted positiqn,r said last means being adapted V toyield in response to actuation of said screews'haft'mfw *d L- Le 4,'. e,

4. The 'combina'bienisJ defined in @rami 3 and includingcna ranipportion; on said screw shaft adapted to coact Wtl 1 s aid holding means when SaidfSQWgSha' isgpgitended to aid linear move- .mOi/@aient there. internal helical i ededmiieii .andan internal netesi toi said. .driving means. 4for..rotation ata different 'rate vthan said spline nut,` means .in

.srogva ASQi'fiitiiieriiiii.@fiiiceiitri with f saidssrew Shaitandextendinetherein, and conawacsa cluding a plurality of spring biased balls associated with said shaft member and adapted to engage said helical threaded portion to provide a screw action for moving said screw shaft axially to an engine engaging position, said spring bias balls being yieldable to permit ratcheting over said helical threads when opposition to said axial movement exceeds a predetermined maximum value, a second plurality of spring biased balls associated with said shaft member and adapted to engage said annular groove when said screw shaft is in a retracted position, said second spring biased balls being yieldable above a predetermined maximum.

6. For use in an engine starter of the type having an axially stationary rotatably splined nut, a screw shaft splined to said spline nut for rotation with and axial movement relative thereto, a starter jaw connected for rotation with and yieldably biased for axial movement with said screw shaft of a jaw advancing means comprising a screw shaft having an internal helical threaded portion, an internal annular groove portion and a ramp portion, a shaft member concentric with said screw shaft and having an enlarged portion extending therein, first yieldable means for connecting said screw shaft and said enlarged portion to provide a screw action for actuating said screw shaft axially to an extended position, second yieldable means for engaging said annular groove portion for retaining said screw shaft in a retracted position, said second yieldahle means being adapted to yield to said screw action to permit linear movement of said screw shaft and to coact with said ramp portion upon linear movement to provide a snap action to said screw shaft.

RODERICK W. STELZEL.

No references cited. 

